1. Field of the Invention
The present invention relates to the tablet display technical field, and in particular to a GOA (Gate Driver on Array) circuit for tablet display and a display device.
2. The Related Arts
The driver of the current tablet display panel horizontal scan line are mainly achieved by the external IC, the external IC can control the approximate charge and discharge of the horizontal scan lines connected with each panel pixel. GOA technology, meaning Gate Driver on Array technology, can use the original manufacturing process of the tablet display panel to fabricate the driving circuit of the horizontal scan line on the substrate surrounding the display region, making it achieve the driver of the horizontal scan line instead of the external IC. GOA technology can simplify the manufacturing process of the display panel, sparing the IC bonding process on the direction of horizontal scan line, it has opportunity to improve the manufacturing process and reduce the cost, and it can improve the integration of the tablet display panel to make itself more suitable for producing the narrow border or no border display products.
The existing circuit usually comprises cascaded plurality of GOA units, each stage of the GOA units corresponds the driving first stage horizontal scan line. The GOA unit mainly comprises a pull-up part, a pull-up control part, a transfer part, a key pull-down part, a pull-down holding part and a boast capacitor utilized to boost the voltage. The pull-up part mainly makes the clock signal output and become the gate signal; the pull-up control part is responsible for controlling the turn-on time of the pull-up part, which is generally connected with the transfer signal or the gate signal transmitted by the front stage GOA circuit; the key pull-down part is responsible for pulling the gate to low voltage in the first time, namely turning off the gate signal; the pull-down holding part is responsible for holding the gate output signal and the gate signal (commonly called Q point) of the pull-up part on the turn-off status (namely negative voltage), usually there are two pull-down holding module operating alternating; the C boast is responsible for boosting Q point second times, it is conducive to G(N) outputting of the pull-up part.
The purpose of the GOA circuit is to output the scan waveform which is output by the integrated circuit through the circuit operation, turning on the pixel switch and thereby inputting the data signal to the ITO electrode. After inputting the data signal, holding on the data signal content until next frame turning on. During the circuit operation process, because a scan circuit is off in the remaining time of a frame after turning on, the scan circuit turn-off (holding) time is much longer than the scanning time, the stability requirement for thin film transistor in the GOA circuit is very high. The high temperature stability of the GOA circuit is one of important factors affecting the GOA technology application. In the high temperature, the leakage current of the thin film transistor composing the GOA circuit becomes large, the output waveform of the GOA circuit may be abnormal.